The present invention relates to a precabling device in a cabling installation. It also relates to a method of implementing said precabling device.
A particularly advantageous application of the invention lies in the field of precabling buildings by means of precabling tubes.
In general manner, a building is wired using thoroughly standardized infrastructure (EN 50173-ISO 11801). A general distribution frame, usually situated in the basement of the building, distributes vertical cables to floor distribution frames or sub-distribution frames, using service ducts. Thereafter, the floor distribution frames serve a plurality of office access points by means of xe2x80x9chorizontalxe2x80x9d cabling. Thus, the general distribution frame is the point where public network cables are connected to vertical cables, while floor distribution frames receive vertical cables and horizontal cables, together with bypass cables and shared network equipments.
In practice, access points at floor distribution frames are connected in cabling installations, for example in cabling bays. A cabling bay is a structure of standardized dimensions. It may be enclosed by means of a door and partitions, in which case it is referred to as a xe2x80x9ccabinetxe2x80x9d.
A cabling bay is fitted with a plurality of cross-connect panels, some of which constitute arrival points for vertical cables, while others represent departure points for horizontal cables going to access points. In order to share a piece of equipment over a plurality of access points, jumpers, e.g. having single optical fibers, are positioned in such a manner as to interconnect the various cross-connect panels (shelves, drawers, . . . ).
Whether performing precabling or cabling, all of the cross-connect panels are in position in the bay and all of the horizontal cables are previously stowed at the bottom of the bay behind the panels. The bay is then ready for the installer to proceed. The cabling in the bay is fixed and the connections to the equipment drawers are made without difficulty as and when required by cross-connect jumpers passing over the front face of the bay.
The drawback of that precabling or cabling method is that all of the cross-connect panels and all of the horizontal cables must be installed at the beginning of installation, i.e. before actually being used, and that represents a significant cost tied-up in hardware.
To remedy that drawback, it is possible to implement precabling by means of tubes. The installation is thus equipped in two stages: in an initial stage, it receives all of the precabling tubes which are stowed so as to be ready on the cross-connect panels, and then in a second stage, the cables are installed progressively to meet requirements by being blown along the precabling tubes. The advantage of that method is that it does not require all of the cables to be put into place initially, thus reducing initial installation costs. However, the cabling installation must itself be equipped from the beginning with all of the cross-connect panels, which nevertheless involves high levels of investment and overdimensioning of the installation since real requirements are not known a priori, given that cabling is performed as and when requested. Furthermore, in order to be able to install cables progressively in the installation by means of blowing, access must be available to the precabling tubes on a permanent basis, even though they are already stowed to the backs of the cross-connect panels. It is therefore necessary to provide special drawers, e.g. of the slideway type, which makes the installation more expensive. Furthermore, slideway drawers are not suitable for tubes that present some degree of stiffness and/or that are of large diameter (e.g. 8 millimeters (mm) outside diameter) since the bundle of tubes then runs the risk of preventing the drawers from moving. The tubes can also be injured or pinched, which makes them unsuitable for use in subsequent blowing operations. Furthermore, having the precabling tubes pre-stowed to the cross-connect panels leads to a lack of flexibility in the management of cables since the number of outlet connectors on a panel is fixed to some maximum value (e.g. 24), and the number of empty tubes is also fixed even though the number of fibers per tube may vary (e.g. in the range 1 to 8). Finally, the initial cost of the installation remains high since it is necessary to install all of the cross-connect panels at the same time as the precabling tubes. This is particularly true when the cabling installation is not accessible from its rear face as is generally the case in old buildings.
One object of the present invention is to provide a precabling device in a cabling installation that makes it possible to remedy the drawbacks presented by the known method of precabling by means of tubes, in particular the high initial investment cost due to prior installation of all of the cross-connect panels.
This and other objects are attained in accordance with one aspect of the present invention directed to a precabling device in a cabling installation, the device being characterized in that it comprises, inside said installation, at least one stowage module and a plurality of precabling tubes for receiving cables, each of said precabling tubes being fixed to the stowage module in the vicinity of an end thereof.
Thus, the precabling device of the invention makes it possible to organize the cabling installation in a manner that is different in that the precabling tubes can be managed independently of the cables or of the cross-connect panels. As explained in greater detail below, the invention makes it possible to install the precabling tubes in the installation without it being necessary to invest in the cross-connect panels beforehand. The cables are taken to the cross-connect panels that are purchased to match demand, thus providing optimum utilization of the panels in terms of cost.
The invention thus makes it easier to manage tubes and cabling, and also facilitates the blowing operation when, advantageously, said precabling tubes are blow tubes.
The precabling device of the invention is implemented by means of a method, which, according to the invention, comprises the steps consisting in:
putting a cross-connect panel into place in the cabling installation;
inserting a cable into one of said precabling tubes through said end fixed to the stowage module; and
connecting said cable to the cross-connect panel.
In a particular implementation of the method of the invention, said cable is inserted by blowing in a blow tube.
In an advantageous variant embodiment, the precabling device of the invention also comprises at least one second stowage module to which each connection tube is fixed in the vicinity of a first end thereof.
Under such circumstances, in accordance with the invention, provision is made for the step of connecting said cable to the cross-connect panel to comprise a first step consisting in introducing the cable into a connection tube through said first end and in fixing said connection tube to the cross-connect panel via a second end. The cable is inserted merely by being pushed in manually, for example.